Powertrain efficiency comparsion

[LandSurfer]

Does anyone know of a good source of study contrasting the basic differences in efficiency between the following transmissions when used for system drive (not ground drive):

- Mechanical powershift
- Belt drive
- CVT
- Hydrostatic

I have always understood a general rule of thumb when discussing the differences in efficiency (as follows):

- 99-100% efficient for powershift
- 95-97% for belt drive
- 85% for CVT
- 65% for hydrostatic transmission)

Thanks for your assistance.

 

[EdDanzer]

The efficiency of any of systems on your list will depend on how it is designed, sized and measured. A large HP system running at low power may be only 5% efficient yet at some rated speed and power level it may be over 90% efficient. This white paper may provide more information:

http://www.dehyds.com/html/standby_power_white_paper.html

Ed Danzer

http://www.danzcoinc.com

http://www.dehyds.com

 

[GregLocock]

As an example of that a hypoid diff (back axle of car) can have an efficiency as low as 40%, in some operating conditions.

Cheers

Greg Locock

SIGlease see FAQ731-376 for tips on how to make the best use of Eng-Tips.

 

[Tmoose]

http://news.thomasnet.com/images/large/014/14625.jpg

This ingenious motorized milling spindle has an oil lubricated concentric constant mesh gearbox.
Just idling at high speeds it needs considerable internal coolant flow and active lube oil cooling and consumes a few electrical HP.
Efficiency [100 X (0 HP out)]/( several HP in) = 0%